Left: stellar mass distribution of our z> 3 SMGs (green histogram), and z ~ 2 cQGs (Krogager et al. 2014; red histogram). The blue histogram shows the distribution of the estimated final stellar masses of our z> 3 SMGs by assuming that 10% of their putative gas mass content (M_gas derived in Sect. 3.2) is converted into stars by the end of the rapid star formation event. The vertical dashed lines mark the median mass values. Right: the green and blue histograms are as in the left panel, while the red and magenta histograms show the stellar mass distributions of cSFGs from Barro et al. (2014) and Fang et al. (2015), respectively.